This thesis presents the results of a research project which sought to find links between driver subjective ratings and objective measures of vehicle handling. The experimental data used in this project has been made available from a previous research project. The experimental data was collected using a prototype vehicle which was used in 16 different configurations. Objective data was collected based around the ISO defined steady state, step input, and frequency response tests. Subjective assessments were collected from eight trained test drivers using a numerical rating scale to a questionnaire covering various aspects of vehicle handling. Analysis of the subjective assessments has been done to identify any shortcomings that may affect any subsequent analysis. From the literature review, an approach that claims to relate four simple objective metrics to subjective measures of vehicle handling has been developed in two new ways. Firstly, the proposal was tested [1] with the large amount of subjective data available to see if good levels of correlation could be found between the proposed metrics and driver subjective ratings to specific handling questions. Secondly, the method was extended to include further simple metrics to try and improve links between the subjective and objective data [2]. Non-linear relationships in the correlation of subjective vs. objective data have been investigated for the first time [3] using non-linear genetic algorithms, which, in addition have not previously been used to correlate driver subjective ratings with objective measures that describe vehicle handling. From the results, it has been possible to specify ranges of preferred values of objective metrics in order to produce a subjectively satisfying vehicle. Finally, the work discusses how the results obtained can be used by engineers to aid the vehicle design and development process.

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There has been an impetus in recent years to increase railway train speeds and reduce journey times. As train speeds have increased, other problems have manifested themselves, in particular the consequent deterioration in ride quality at these higher operating speeds. Improvement in suspension design is one option which can circumvent this problem. Suspension design for a modem high-speed train has hitherto been a heuristic procedure directed towards optimising the passive components of the suspension. Performance limits are now being reached with passive suspensions due to the inherent trade-offs which need to be made in the design process. Active suspension, which eases this inherent trade-off, has received a great deal of interest in both academia and industry over recent years. A number of theoretical and experimental studies have highlighted the potential benefits of active suspension technology. Theoretical studies have concentrated on using simple vehicle models and although providing the initial impetus to active suspension they have not given the industry full confidence in them. In contrast, experimental studies have highlighted a number of problems, most notably the significant effect actuators can have on the overall performance.

The conflict between stability and curving has been well documented since the dawn of the railways. Advances in computer technology and deeper understanding of the complex mechanics of the wheel-rail interface have led to the study of innovative designs. This thesis outlines the need for steering systems for railway applications. A number of innovative passive solutions have been proposed to reduce the conflict between stability and curving. Comparisons of some of these solutions show that significant benefits can be obtained by using uncommon configurations.

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